You were clearly mistaken. dataframe$column is almost the same as dataframe[["column"]], except that the $ does partial matching. Both of these "extract" a list element.
A data frame is a list where all elements are vectors of the same length. A list is a vector where each element can refer to any of a variety of types of objects. The names of the objects in the list are associated with the list vector, not the referred objects (e.g. columns). The [] operator "slices" the list but keeps the names and referring semantics. The [[]] extraction operator (and its pal $) refer to a single element out of the list, losing access to the containing list and the names that go with it. The Introduction to R document has all this in it... it just usually glazes your eyes the first few times you read it. You might find the R Inferno more entertaining. -- Sent from my phone. Please excuse my brevity. On May 30, 2016 11:45:52 PM PDT, g.maub...@weinwolf.de wrote: >Hi All, > >I thought dataset$variable is the same as dataset["variable"]. I tried >the >following: > >> str(ZWW_Kunden$Branche) >chr [1:49673] "231" "151" "151" "231" "231" "111" "231" "111" "231" >"231" >"151" "111" ... >> str(ZWW_Kunden["Branche"]) >'data.frame': 49673 obs. of 1 variable: > $ Branche: chr "231" "151" "151" "231" ... > >and get different results: "chr {1:49673]" vs. "data.frame". First one >is >a simple vector, second one is a data.frame. > >This has consequences when subsetting a dataset and filter cases: > >> ZWW_Kunden["Branche"] %in% c("315", "316", "317") >[1] FALSE > >> head(ZWW_Kunden$Branche %in% c("315", "316", "317")) # head() only to > >shorten output >[1] FALSE FALSE FALSE FALSE FALSE FALSE > >I have thought dataset$variable is the same as dataset["variable"] but >actually it's not. > >Can you explain what the difference is? > >Kind regards > >Georg > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.